System for supplying hydraulic pressure to a bolt elongation tool

Abstract

System for supplying hydraulic pressure to a bolt elongation tool, comprising the bolt elongation tool with at least one pressure chamber and a tool piston, a hydraulic medium supply system and a hydraulic actuator with an actuator cylinder housing an actuator piston. The actuator cylinder is attached to the at least one pressure chamber, wherein the hydraulic actuator is an electro-hydraulic actuator comprising an electric motor built to generate the power of the electro-hydraulic actuator, and wherein the actuator piston is built to supply, with one stroke of an actuator stroke height of the actuator piston, at least the amount of hydraulic pressure that is needed to move the tool piston for the amount of one tool stroke height of the tool piston.

The invention claimed is: 
     
       1. System for supplying hydraulic pressure to a bolt elongation tool, comprising the bolt elongation tool with a pressure chamber and a tool piston, a hydraulic medium supply system including a reservoir that fluidly communicates directly with the pressure chamber by way of a gate in the bolt elongation tool, and a hydraulic actuator with an actuator cylinder housing an actuator piston,
 wherein the actuator cylinder is selectively connectible to the pressure chamber in a pressure-tight and liquid-tight manner in order to supply via the pressure chamber the hydraulic pressure by a hydraulic medium to the tool piston, 
 wherein the hydraulic actuator is an electro-hydraulic actuator comprising an electric motor operable to generate the power of the electro-hydraulic actuator and that the actuator piston is built to supply, with one stroke of an actuator stroke height of the actuator piston, at least a volume that is needed to move the tool piston for an amount of one tool stroke height of the tool piston, and 
 wherein the actuator cylinder is configured so that when the actuator piston is in a fully extended state, the actuator piston prevents fluid communication between the actuator cylinder and the reservoir, and the actuator piston prevents fluid communication between the actuator cylinder and the pressure chamber, so as to maintain hydraulic pressure in the pressure chamber. 
 
     
     
       2. System according to  claim 1 , wherein the actuator cylinder and the pressure chamber are detachable from, and attachable to, one another in order to supply, via the actuator cylinder and the pressure chamber, the amount of hydraulic pressure that is needed to move the tool piston for the amount of one tool stroke height of the tool piston. 
     
     
       3. System according to  claim 1 , wherein when the actuator piston is fully retracted, both the reservoir and the pressure chamber are in fluid communication with the actuator cylinder. 
     
     
       4. System according to  claim 1 , wherein the system comprises a short stiff hollow connector connecting the actuator cylinder at an outlet with at least one inlet of the pressure chamber, which connector enables the actuator cylinder and the pressure chamber to be detachable from and attachable to, one another in order to supply, via the actuator cylinder and the pressure chamber, the amount of hydraulic pressure that is needed to move the tool piston for the amount of one tool stroke height of the tool piston. 
     
     
       5. System according to  claim 1 , wherein the one tool stroke height of the tool piston is smaller than the actuator stroke height of the actuator piston. 
     
     
       6. System according to  claim 1 , wherein the electro-hydraulic actuator comprises a spindle housing, housing a spindle axially connected to a spindle nut, which spindle housing is connected to the actuator cylinder at a second end of the spindle housing, wherein the electric motor is axially connected to the spindle nut at a first end of the spindle housing and built to rotate the spindle nut in order to move the spindle substantially linearly along an axial direction of the electro-hydraulic actuator, and the spindle does not rotate as it moves along the axial direction. 
     
     
       7. System according to  claim 6 , wherein the electric motor is operable to rotate the spindle nut via a toothed belt wrapped around a first gear wheel, wherein the electric motor is operable to rotate the first gear wheel, and around a second gear wheel axially connected to the spindle nut, wherein a diameter of the second gear wheel is larger than a diameter of the first gear wheel. 
     
     
       8. System according to  claim 6 , wherein the spindle at a second end is connected to a first end of the actuator piston via a spindle slider engaging into guiding grooves formed at an inside of the spindle housing, wherein the guiding grooves run substantially linearly along the axial direction, and wherein the spindle nut is built to move the spindle and the spindle slider along the axial direction. 
     
     
       9. System according to  claim 6 , wherein the spindle housing at its second end is connected to the actuator cylinder via a piston housing with a bleed gate operable to bleed the space surrounding the actuator piston, wherein the piston housing is operable to guide the actuator piston, which is sealed at the interface to the piston housing with a dynamic sealing. 
     
     
       10. System according to  claim 1 , further comprising a spindle housing, that houses a spindle axially connected to a spindle nut, wherein the electric motor is operable to rotate the spindle nut in order to move the spindle along an axial direction, and wherein the spindle at a second end is connected to a first end of the actuator piston, via a spindle slider engaging into guiding grooves formed at an inside of the spindle housing and running substantially linearly along the axial direction of the electro-hydraulic actuator. 
     
     
       11. Electro-hydraulic actuator according to  claim 10 , wherein the electro-hydraulic actuator is attachable and detachable to the bolt elongation tool in order to supply the amount of hydraulic pressure that is needed to move the tool piston for the amount of one tool stroke height of the tool piston. 
     
     
       12. Electro-hydraulic actuator according to  claim 10 , wherein the electro-hydraulic actuator at an outlet of the actuator cylinder comprises a short stiff hollow connector operable to enable the electro-hydraulic actuator being attachable or detachable to the bolt elongation tool in order to supply the amount of hydraulic pressure that is needed to move the tool piston for the amount of one tool stroke height of the tool piston. 
     
     
       13. Electro-hydraulic actuator according to  claim 10 , wherein the actuator cylinder or a connector comprise at least one security valve built to prevent leakage of the hydraulic medium. 
     
     
       14. Electro-hydraulic actuator according to  claim 10 , wherein the electric motor is operable to rotate the spindle nut via a toothed belt wrapped around a first gear wheel, wherein the electric motor is operable to rotate the first gear wheel, and around a second gear wheel axially connected to the spindle nut, wherein a diameter of the second gear wheel is larger than a diameter of the first gear wheel. 
     
     
       15. Electro-hydraulic actuator according to  claim 10 , wherein the electro-hydraulic actuator is sized and configured to be manually held. 
     
     
       16. System as recited in  claim 1 , wherein when the bolt elongation tool is engaged with a bolt, movement of the actuator piston to the fully extended position causes the bolt to elongate. 
     
     
       17. System for supplying hydraulic pressure to a bolt elongation tool, comprising the bolt elongation tool with a pressure chamber and a tool piston, a hydraulic medium supply system including a reservoir that fluidly communicates directly with the pressure chamber, and a hydraulic actuator with an actuator cylinder housing an actuator piston,
 wherein the actuator cylinder is connected to the pressure chamber in a pressure-tight and liquid-tight manner in order to supply via the pressure chamber the hydraulic pressure by a hydraulic medium to the tool piston, 
 wherein the hydraulic actuator is an electro-hydraulic actuator comprising an electric motor operable to generate the power of the electro-hydraulic actuator and that the actuator piston is built to supply, with one stroke of an actuator stroke height of the actuator piston, at least a volume of the hydraulic medium that is needed to move the tool piston for an amount of one tool stroke height of the tool piston, 
 wherein the system is configured to supply a pressure of at least 1000 MPa, and 
 wherein the actuator cylinder includes a first fluid connection and a second fluid connection, and: 
 when the actuator piston is in a fully retracted state, the actuator cylinder is connected to the reservoir by the first fluid connection, and actuator cylinder is connected to the pressure chamber by the second fluid connection; and 
 when the actuator piston is in a fully extended state, both the first fluid connection and the second fluid connection are blocked by the actuator piston so as to maintain hydraulic pressure in the pressure chamber. 
 
     
     
       18. A system, comprising:
 a bolt elongation tool including a pressure chamber and a tool piston, the pressure chamber configured to supply a pressurized hydraulic medium to a surface of the tool piston, and the bolt elongation tool configured to releasably engage a bolt; 
 a hydraulic system including a reservoir configured for fluid communication with the pressure chamber, and for fluid communication with an actuator cylinder within which is received an actuator piston; 
 a motor at least indirectly connected to the actuator piston, and the motor is operable to move the actuator piston within the actuator cylinder, and 
 wherein the actuator cylinder is configured so that when the actuator piston is in a fully extended state: the actuator piston prevents fluid communication between the actuator cylinder and the reservoir; and the actuator piston prevents fluid communication between the actuator cylinder and the pressure chamber. 
 
     
     
       19. The system as recited in  claim 18 , wherein when the actuator piston is in the fully extended state, the actuator piston maintains hydraulic pressure in the pressure chamber. 
     
     
       20. The system as recited in  claim 18 , wherein when the bolt elongation tool is engaged with the bolt, movement of the actuator piston to the fully extended position causes a corresponding movement of the tool piston to elongate the bolt.